Browsing by Subject "vibration isolation"

Now showing 1 - 3 of 3

Access status: Open Access ,
Application of LQR theory to optimization of vibration isolation of sitting human body
(Wydawnictwa AGH, 2008) Książek, Marek A.; Ziemiański, Daniel
In the paper the linear quadratic regulator (LQR) theory was applied to optimization of vibration isolation system of sitting human operator body subjected to vertical excitations. The optimization approach was applied to system composed of active human body model (AHBM) and passive, linear vibration isolation system (VIS). Synthesis of optimal LQR for the given system was done for two existing, active biodynamical models «back-off» and «»back-on» of sitting human body. Optimization was done for chosen form of vibration isolation criterion. Analytical formula of that form, corresponding to present standards concerning the human body expositions to vibration, was presented. Influence of the LQR on dynamical behavior of the system composed of AHBM and VIS was estimated on the basis of numerical calculations, discussed and graphically presented.
Access status: Open Access ,
Dynamics of active biomechanical models of seated human body and their vibration isolation systems
(Wydawnictwa AGH, 2005) Książek, Marek A.; Janik, Artur
In the paper the dynamic behaviour of the systems composed of active human body models (AHBM) and passive isolation systems (VIS) subjected to sinusoidal and random excitations was discussed. The two active human body biomechanical models («back-off» and «back-on») obtained several years ago by the first author of the presented paper can be considered as active, linear, stable, lumped parameter and unidirectional dynamical systems. These models «seated» on passive vibration isolation systems (VIS) make new, coupled dynamical models (AHBM+VIS). In the first part of the presented paper the dynamical characteristics of the coupled, linear models (AHBM+VIS) were thoroughly analyzed. The new maps of poles distribution of characteristic equations of the systems composed of the coupled models show, that in some cases, these systems can be unstable. In the paper the stability areas were numerically estimated and graphically presented for the simplest, linear vibration isolation system. In the second part of the paper the influence of some chosen nonlinear elements injected into VIS on the amplitudes of chosen model mass accelerations and relative displacements between them was estimated, basing on the results obtained from the simulation approach. The simulation investigations were done for a sequence of time delay of the VIS reactions and sinusoidal excitations. The sinusoidal excitations had variable amplitudes and the frequencies corresponding to the first resonant frequency of the considered AHBM+ VIS systems. The values of the corresponding amplitudes of output signals were compared. In chosen cases where the simulations were done for the random excitations the root mean square values of the output signals were compared. The obtained results were compared with the simplest linear VIS, graphically presented and discussed.
Access status: Open Access ,
Investigations of influence of vibration on human-operator control functions
(2010) Basista, Zygmunt; Książek, Marek A; Tarnowski, Janusz
In the paper results of experimental investigations of the system operator-handle-base have been presented. The aim of investigations was to record and analyse dynamical reactions of human operator volunteers participating in the experiments on a visual, suddenly appearing step signal. The main task of each operator was tracking of the signal as precisely as possible with a push force exerted on the tool handle. The measurements were done on an especially designed stand. The stand allows to simulate vibration of the tool with chosen frequencies with or without handle isolation. Time histories of step reference and forces realized by the operator were statistically elaborated and graphically presented.